To further increase the storage areal density of the hard disk drive (HDD) system, there has been a growing demand for improving the performance of magnetic recording heads. In a current perpendicular magnetic recording (PMR) head, a single pole writer with a tunneling magnetoresistive (TMR) reader provides a high writing field and a large read-back signal to achieve a higher areal density.
The single pole writer consists of a main pole (MP) surrounded by magnetic shield materials from which the MP is separated by a nonmagnetic spacer layer. The MP has a tapered shape whose tip faces the magnetic media as well as serving as an air bearing surface (ABS). In addition to the MP and the magnetic shield materials, a single pole writer also includes a pair of pancake-like conductive coils. These two coils are connected through a center tab, with one placed above the MP and the other under the MP perpendicular to the ABS direction. During writing, an electric current is applied through the coils, causing a large magnetic field to be generated from the MP tip. This field is used to change the polarity of the magnetic media.
An MP ABS view of a prior art design is shown in FIG. 1. In ABS view the MP body 13 has a triangular or trapezoidal shape. As seen, the MP width (PW) defines the track width in the media. Soft magnetic shield materials 15 are used around the MP with a nonmagnetic spacer in between. The nonmagnetic space 14 on the two sides of the MP is called the Side Gap (SG) and the nonmagnetic space 12 above the MP is called the Write Gap (WG). Above the WG, a high magnetic magnetization material 11, such as Fe(1-x)Co(x) (x=20-55 at %), Fe(1-y)Ni(y) (y=5-55 at %) etc, is deposited above the MP write gap 12. This high magnetic magnetization layer 11 is the so-called “hot seed”.